Cannula-based irrigation system and method

ABSTRACT

A retractor and a surgical tool are positioned within a cannula, and a dissection cradle of the retractor is positioned at the distal end of the cannula. The retractor includes a first portion with an axis approximately parallel to the axis of the cannula and a second portion with an axis skewed relative to the axis of the cannula. The dissection cradle may include two substantially parallel, spaced legs with the retractor shaped in a loop between and in a plane skewed relative to the axes of the legs, and with the loop directed away from the surgical tool. Thus, in operation, when a surgeon locates a vessel and side branch of interest, the surgeon extends the retractor to cradle the vessel in the dissection cradle. Once cradled, the retractor may be fully extended to urge the vessel away from the axis of the cannula to isolate the side branch for exposure to a surgical tool. One of the legs supporting the retractor is hollow and includes a spray nozzle disposed in the distal end of the retractor to form an irrigation system. The proximal end of the hollow leg communicates with a fluid inlet which receives irrigation fluid under pressure for washing the endoscope lens. The spray nozzle on the retractor may be positioned to wash the endoscope lens, or upon selective extension of the retractor out of the cannula, the spray nozzle may be positioned to direct the spray of irrigation fluid at a remote surgical site.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a continuation-in-part application ofapplication Ser. No. 09/102,723 filed on Jun. 22, 1998, now U.S. Pat.No. 5,895,353 which prior application is assigned to the same assigneeas the present application.

FIELD OF THE INVENTION

This invention relates to a cannula used for endoscopic surgery, andmore particularly to a cannula and method for maintaining a clear visualfield for an endoscope housed within the cannula.

BACKGROUND OF THE INVENTION

Endoscopic surgery allows a surgeon to perform safe and successfulprocedures because of the surgeon's ability to view the surgical sitethrough the endoscope lens. For some surgical procedures, such asdissection, the cannula housing the endoscope has a transparent bluntdissection tip through which the surgeon views the surgical site. Theblunt dissection tip protects the endoscope lens from being smeared byblood or fatty tissue present at the surgical site, or from being foggeddue to the moist subcutaneous environment. However, many surgicalprocedures cannot be performed using a blunt dissection tip. When sidebranches and vessel ends of a vessel must be transected to harvest thevessel, the end of the cannula must be open to allow the surgical toolsto extend from the cannula. When the cannula end is open, the endoscopelens is subject to the adverse conditions described above. The surgeonis forced to repeatedly remove the cannula from the body to clean theendoscope lens. This increases the length and risks of the operation.

Some conventional schemes for cleaning an endoscope lens rely upon anendoscope with a cleaning system built within it. However, having acleaning system within the endoscope restricts the angle of incidence atwhich the cleaning fluid may be propelled toward the lens to almostparallel to the lens. This results in a less effective cleansing action.Also, since the spray is being directed parallel to the lens, thesurgeon cannot see the spray source and it is therefore difficult toadjust the direction of the spray. Thus, with these systems, theendoscope must still be removed on occasion for manual cleaning wherethe proper angle of incident spray can be obtained manually.Additionally, in procedures using gas insufflation, the gas may dry outa target vessel or other surgical site. In these situations, it is oftennecessary to irrigate the vessel to prevent the vessel from drying out.However, conventional endoscope washing systems are not capable ofproviding both endoscope lens cleaning and remote surgical siteirrigation. Therefore, a remote endoscopic washing system would bedesirable for more effectively cleansing the endoscope lens during asurgical procedure by allowing the surgeon to control the angle at whichcleansing fluid is sprayed as well as allowing the surgeon to use thesame apparatus to irrigate the surgical site itself.

SUMMARY OF THE INVENTION

In accordance with the present invention, a retractor is positionedwithin a cannula with a dissection cradle end of the retractorpositioned at the distal end of the cannula. The retractor includes afirst portion that has an axis approximately parallel to a central axisof the cannula, and a second portion that has an axis which is at anangle with respect to the central axis of the cannula. The dissectioncradle is located at the distal end of the second portion of theretractor. In another embodiment, the retractor includes two legs havingsubstantially parallel axes that selectively protrude from the distalend of the cannula. The protruding legs support the dissection cradleformed in the shape of a partial loop that is positioned in a planeskewed relative to the axes of the legs, with a bottom of the loopdirected away from the cannula. Thus, in operation, when the surgeonlocates a vein and side branch of interest, the surgeon extends theretractor to cradle the vein in the dissection cradle. Once cradled, theretractor may be fully extended, displacing the vein away from the axisof the cannula, causing the side branch to be isolated and exposed to asurgical tool. The surgical tool may then be extended from within thecannula to operate on the isolated and exposed side branch.

In accordance with one embodiment of the present invention, a remoteirrigation system is built into the cannula. In one embodiment, one ofthe legs which comprise the retractor of the present invention ishollow, and is attached to a spray nozzle disposed in the distal end ofthe retractor. The proximal end of the hollow leg is attached to a fluidinput tube which selectively provides irrigation fluid under pressurefor washing the endoscope lens. When extended slightly beyond the distalend of the cannula, the spray nozzle is positioned to direct the sprayof irrigation fluid at an angle approximately normal to the endoscopelens. This provides for an extremely effective cleaning action, andminimizes the need for removal of the endoscope during surgicalprocedures for manual cleaning. Additionally, if the surgical siteitself requires irrigation, the retractor is extended out of the cannulatoward the area requiring irrigation, and an irrigation fluid can besprayed directly on the site. Finally, as the spray is directed backtoward the lens, the surgeon can visually adjust the extension of theretractor to accurately direct the spray toward the lens or surgicalsite.

In a further embodiment, the hollow leg moves within a lumen in thecannula in fluid-resistant sliding engagement, and the fluid input tubeis coupled to this lumen. In this embodiment, the maximal outerdimension of a region of the hollow leg is slightly less than a maximalinner dimension of the lumen. The slip-fit, fluid-resistant coupling ofthe hollow leg within the lumen allows irrigation fluid to be introducedat the proximal end of the lumen by the fluid input tube withoutsignificant leakage past the sliding juncture of the hollow leg withinthe lumen.

In an alternate embodiment, the hollow leg includes a semi-rigid plastictubing, and fits within an irrigation tube which lines the inside of thelumen. The fluid input tube attaches to the irrigation tube and extendsout of the cannula handle for receiving irrigation fluid. The use offlexible, semi-rigid plastic tubes provides fluid seals throughout theirrigation system to minimize leakage. In a third embodiment, thecannula contains a separate irrigation lumen which has a spray nozzledisposed in a fixed position at its distal end. The spray nozzle ispositioned within the cannula to allow the proper angle of incidence forthe spray to effectively clean the lens. Finally, in another embodiment,the dissection cradle is supported by only one leg, and the lumen whichpreviously held the second leg instead is fitted with a spray nozzledirected toward the endoscope lens. An embodiment is also disclosed inwhich a nozzle tube situated within a cannula lumen is selectivelyextensible responsive to the application of hydraulic pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a preferred embodiment of cannula 100showing retractor 112 in an extended position.

FIG. 2 a is a cut-away side view of retractor 112 and cannula 100.

FIG. 2 b is a top view of retractor 112.

FIG. 3 a is a perspective side view of cannula 100 with a saphenous veinpositioned within the cradle 116.

FIG. 3 b is a perspective side view of the distal end 122 of cannula 100in an embodiment in which an endoscope 126 and a surgical tool 120 arepresent and partially extended.

FIG. 3 c is a front view of the distal end 122 of cannula 100 in whichthe surgical tool 120 and the retractor 116 are partially extended, andan endoscope 126 is present.

FIG. 4 a is a cut-away top view of cannula 100.

FIG. 4 b is a cut-away side view of cannula 100.

FIG. 5 a is a cut-away view of a sliding tube embodiment of cannula 100in a first position.

FIG. 5 b is a cut-away view of the sliding tube embodiment of FIG. 5 ain a second position.

FIG. 6 a is a cut-away view of an embodiment of cannula 100 having anangling device 140.

FIG. 6 b is a cut-away side view of the apparatus illustrated in FIG. 6a in which the retractor 112 is extended and the angling device 140 isactuated.

FIG. 6 c is a cut-away side view of the angling device embodiment inwhich the angling device 140 is in a separate lumen from the retractor112.

FIG. 7 a is a cut-away side view of a twistable retractor 112 in astraight position.

FIG. 7 b is a side view of the retractor 112 of FIG. 7 a.

FIG. 7 c is a cut-away side view of twistable retractor 112 in a crossedposition.

FIG. 7 d is a side view of the retractor 112 of FIG. 7 c.

FIG. 8 a is a cut-away side view of the handle 104.

FIG. 8 b is a cut-away side view of an alternate embodiment of handle104.

FIG. 9 a is a side view of cradle 116.

FIG. 9 b illustrates a first alternate embodiment of cradle 116.

FIG. 9 c illustrates multiple views of a second alternate embodiment ofcradle 116.

FIG. 9 d illustrates multiple views of a third alternate embodiment ofcradle 116.

FIG. 9 e illustrates multiple views of a fourth alternate embodiment ofcradle 116.

FIG. 9 f illustrates multiple views of a fifth alternate embodiment ofcradle 116.

FIG. 9 g illustrates multiple views of an embodiment of cradle 116having a spur.

FIG. 10 a illustrates a top view of an embodiment of the cradle 116 ofFIG. 9 c without a “C” ring.

FIG. 10 b illustrates a side view of the cradle 116 of FIG. 10 a.

FIG. 10 c illustrates a top view of the cradle 116 of FIG. 9 c with the“C” ring attached.

FIG. 10 d illustrates a side view of the cradle 116 of FIG. 10 c.

FIG. 11 a illustrates a perspective side view of a cannula 100 includingan irrigation system integrated with the retractor 112.

FIG. 11 b is a cut-away view of a retractor 112 of FIG. 11 a modified toincorporate the irrigation system.

FIG. 11 c is a cut-away view of a modified retractor 112 and endoscope126 situated in a cannula 100.

FIG. 11 d is an alternate embodiment of the cannula-based irrigationsystem of FIG. 11 a.

FIG. 12 is a cut-away side view of a multi-tube embodiment of anirrigation system.

FIG. 13 is a cut-away side view of an irrigation system including aseparate lumen.

FIG. 14 a is a perspective front view of a single leg irrigation system.

FIG. 14 b is a perspective side view of the single leg irrigationsystem.

FIG. 15 is a flowchart illustrating a method of cleansing an endoscopiclens and irrigating a surgical site in accordance with the presentinvention.

FIG. 16 a is a cut-away side view of an alternate embodiment of acannula-based irrigation system in accordance with the presentinvention.

FIG. 16 b illustrates the embodiment of FIG. 16 a when the nozzle 1600is under hydraulic pressure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a perspective view of a preferred embodiment ofcannula 100 showing retractor 112 in an extended position. Cannula 100includes an outer housing 102 of bioinert material such as polymed UDthat may be approximately 12″ to 18″ in length. The proximal end of thecannula 100 is disposed in handle 104 that includes a button 106 whichis coupled to retractor 112 for controlling the translational movementof retractor 112, as described in more detail below.

The distal end of the cannula houses a retractor 112, and optionally anendoscope 126 and a surgical tool 120, described below. FIG. 2 aillustrates the retractor 112 in more detail. In one embodiment,retractor 112 is formed of resilient wire which has a smooth bendintermediate to a first portion 110 and a second portion 114 of theretractor. The retractor 112 is described as having two portions forease of description, although the retractor 112 may be formed as anintegrated structure. However, retractor 112 may also be manufacturedfrom two separate portions 110, 114 that are coupled together. The firstportion 110 of the retractor 112 is positioned within the cannula 100with the axis 111 of the first portion 110 approximately parallel to theaxis 101 of the cannula 100. The second portion 114 is positioned tobend away from the central axis 101 of the cannula. The angle 117 ofdisplacement between the axis 115 of the second portion and the centralaxis 101 of cannula 100 may be any angle from zero to 180 degrees. Thesecond portion 114 includes a dissection cradle 116 at the distal end ofthe second portion 114. The retractor 112 may be formed of bioinertmaterial such as stainless steel, or a polymer such as nylon orpolyetherimide, or other appropriately strong and resilient plastic. Inone embodiment, the retractor 112 includes a coating for lubrication,insulation, and low visual glare using, for example, parylene or nylon11.

FIG. 2 b illustrates the retractor 112 formed with two legs. The legs141, 142 of the retractor 112 at the distal end form the dissectioncradle 116 in a loop or “U” shape, as shown in FIG. 2 a. The top portion144 of the U-shaped bend is preferably flattened to provide additionalsurface area for atraumatically supporting a vein 118 or vessel ofinterest. The side arches 128 of the dissection cradle 116 are used forskeletonizing or dissecting the vein from the surrounding tissues, aswell as acting as walls to keep the vessel captured within the arch. Theseveral embodiments of dissection cradle 116 are described in moredetail below.

FIG. 3 a illustrates a perspective view of the cannula 100 in accordancewith the present invention with the retractor fully extended, holding asaphenouss vein 118, and also illustrates an external surgical tool 120disposed adjacent the cannula 100 for performing a surgical operation,for example, severing a tributary or side branch of the vein 118. Thevein is positioned within the side arches 128 of the cradle 116. Thedissection cradle 116 may be used to cradle a vein, vessel, tissue ororgan of interest, and surgical tool 120 may be any surgical toolsuitable for performing a surgical procedure near the dissection cradle116.

FIG. 3 b illustrates a perspective view of cannula 100 in an embodimentin which the surgical tool 120 is positioned within the cannula 100, andan endoscope 126 is present. In this embodiment, cradle 116 preferablyoverlays the endoscope 126 with sufficient clearance to facilitaterelative movements thereof However, the endoscope may also be locatedadjacent the surgical tool 120. In one embodiment, endoscope 126 ispositioned with cannula 100 to allow a clear field of view uponextension of the retractor 112. Surgical tool 120 is illustrated ascauterizing scissors, used to sever a tributary or side branch of asaphenouss vein 118. In this embodiment, surgical tool 120 is maximallydisplaced from the cradle 116 at the cannula end 122. More specifically,as shown in FIG. 3 c, the “U”-shaped loop 129 of the cradle 116 isclosest to the surgical tool 120. This ensures that a vein 118 or othertissue of interest is retracted away from the surgical tool 120 tofacilitate manipulating the surgical tool 120 relative to the sidebranch or other tissue.

FIG. 4 a is a cut-away top view of cannula 100. The retractor 112 isslidably positioned within minor lumens 113 along the length of thecannula 100 within close tolerances in order to position the retractor112 stably within the cannula 100. For example, in one embodimentretractor legs 141, 142 are approximately 0.045 inches in diameter andthe lumens 113 encasing the legs 141, 142 are approximately 0.080 inchesin diameter, as friction between the legs of the retractor 112 and thelumens 113 holds the retractor stably within the cannula. Thisconfiguration restricts rotational movement of the retractor to providemore stable retraction as compared with conventional retractors. Thelegs 141, 142 of the retractor 112 are formed of flexible, resilientmaterial and are retained within the lumen 113 in substantially straightor flat orientation, but may return to a material bend or curve, asillustrated in FIG. 5 a, as the retractor 112 is extended from thedistal end of the cannula 100.

The leg 141 of the retractor 112 passes through a sliding gas or fluidseal 130 at the proximal end of the lumen 113. The leg 141 of theretractor 112 passes out of the cannula 100 and into handle 104 forattachment to a slider button 106 for facilitating translationalmovement of the retractor 112 from the proximal or handle end of thecannula 100. However, other types of control devices such as knobs,grips, finger pads, and the like may be linked in conventional ways tothe retractor 112 in order to manually control the translationalmovement of retractor 112. In one configuration, the proximal end of leg141 is bent relative to the axis of the cannula, and the button 106 isattached to the bent position of the leg 141 to facilitate moving thebutton 106 and the retractor 112 translationally under manual control.The button 106 preferably includes lateral grooves to prevent finger orthumb slippage during sliding manipulation of the retractor 112.

Thus, in the operation of a preferred embodiment, a user actuates theslider button 106 to extend retractor 112 out of the lumen 113 at thedistal end of the cannula 100. In one embodiment, the resilientretractor 112 is formed in a smooth bend, as shown in FIG. 2 a, andgradually deflects away from the central axis 101 of the cannula 100 asthe retractor is extended. Upon encountering the target vessel or tissueof interest, the vessel is restrained in the cradle 116, and a lateralresilient force is exerted on the target vessel in a direction away fromthe cannula. The vessel is thus pushed away from the axis of the cannula100, isolating it from surrounding tissue or adjacent vessels such astributaries or side branches. As a tributary is thus isolated, asurgical tool 120 such as cauterizing scissors may be safely employed tooperate on the tributary without harming the saphenouss vein 118. Whenretracted into the cannula 100, the retractor 112 is again resilientlystraightened or flattened.

In an alternate embodiment as illustrated in FIGS. 5 a and 5 b, asliding tube 132 is added to provide operational versatility to cannula100. In a first position, the sliding tube 132 is retracted and theretractor 112 protrudes from the distal end at an angle with respect tothe central axis 101 of the cannula 100. In a second position, thesliding tube 132 is extended out, temporarily straightening theretractor 112. As illustrated in FIG. 5 a, a sliding tube 132, in afirst position encases the retractor 112 up to the point at which theretractor 112 curves away from the central axis 101 of the cannula thusallowing the retractor 112 to displace and isolate a target vessel. Theproximal end of the sliding tube 132 is linked to button 107 fortranslationally moving retractor 112 as well as actuating the slidingtube 132. In one embodiment, as illustrated in FIG. 5 a, the slidingtube 132 is in a first position with the button 107 in an uprightposition. A spring 134 is coupled between a support structure 135 andthe proximal end 137 of the sliding tube 132. In the first position ofsliding tube 132, the spring 134 is extended filly and exerts little orno force on the sliding tube 132. Of course, sliding tube 132 may bemanually manipulated without linkage to a button 107.

To extend the sliding tube 100, button 107 is pushed down. Asillustrated in FIG. 5 b, the button 107 has a cam surface 136 whichpushes on the proximal end 137 of the sliding tube 132 as the button 107is pressed. The sliding tube 132 is pushed forward, overcoming theresilient force of spring 134, to encase the retractor 112 and decreaseangle 117 between the distal end of the retractor 112 and the centralaxis 101 of the cannula 100. Upon releasing the button 107, the springforce urges the proximal end 137 of the sliding tube 132 back toward thefirst position against button 107. The sliding tube 132 is formed ofmaterial having sufficient strength to force the retractor 112 tostraighten out the angle 117, and the retractor 112 is formed ofresilient material having a sufficient flexibility to straighten out theangle 117 in response to a tube 132 being slid over the retractor 112,but having sufficient rigidity to cradle and dissect a target vessel.Resiliency of the retractor 112 ensures return to the downwardly-curvedshape after being released from tube 132. Thus, in accordance with thisembodiment, a user may employ the curved retractor for certainapplications and employ the straightened form for other applications. Amanual actuator may be configured in other ways than button 107 toextend the sliding tube 132 in response, for example, to being pulled upinstead of pushed down.

Another embodiment employs a retractor 112 which has a naturallystraight shape. As illustrated in FIGS. 6 a and 6 b, an angling device140 is disposed between the distal end of the retractor 112 and theproximal end of the cannula. The angling device 140 may be positionedwithin the same lumens 113 as the retractor 112 and preferably maycomprise two wires coupled to points below the cradle 116 of theretractor 112 substantially in parallel positions on each of the legs141, 142.

Upon extending the retractor 112 using button 106, the angling device140 is extended with the retractor 112. The angling device 140 iscoupled to a handle 145 at the proximal end of the cannula 100 tofacilitate establishing an angle in the retractor 112 by pulling with abackward force on the angling device 140. As illustrated in FIG. 6 b,after the retractor 112 is extended, the angling device 140 is actuatedand a bend is created in the retractor 112 as the backward force exertedon the distal end of the retractor is exerted against the relativelyfixed position of the retractor legs 141, 142 disposed within the lumens113. As shown in FIG. 6 c, the angling device 140 may also be located ina separate lumen 202 from the retractor 112 with part of the anglingdevice 140 positioned outside of the cannula 100 when the retractor 112is in the retracted position.

FIG. 7 a illustrates another embodiment of cannula 100 in which theretractor 112 is pre-formed with one leg 141 of the retractor 112 bentat an angle at its proximal end skewed to the axis of the distal end ofthe other leg 142. The bent portion of the leg 141 may be linked to asliding knob 147 for convenient manual manipulation of this embodimentof the invention. Upon sliding the knob 147, the leg 142 coupled to knob147 is twisted rotationally. The two legs 141, 142 of retractor 112 arecoupled together via cradle 116. The axis of the second portion of theretractor 112 in the first position is at a first angle 117 to the axisof the cannula 100, as shown in FIG. 7 b. As knob 147 is moved, leg 141is rotated and crosses under leg 142, as shown in FIG. 7 c. This causescradle 116 to flip 180 degrees and bends the retractor 112 at a secondangle 119, as shown in FIG. 7 d. Thus, if a vessel is disposed on oneside of cradle 116 or cannula 100 while the retractor 112 is in thefirst position, then upon rotating the knob 147, the vessel istransported to the other side of the cannula 100. This allows the userto isolate the vessel by simply actuating knob 147.

FIG. 8 a illustrates a cut-away side view of button 106 on the handle104 of cannula 100, with an endoscope 126 positioned within cannula 100.As mentioned above, button 106 is coupled to one leg 141 of the proximalend of retractor 112. Sliding the button 106 in groove 146translationally moves the retractor 112. Groove 146 is preferablyminimally wider than the shaft of button 106 to minimize excessivehorizontal movement of button 106 while still allowing smoothtranslational movement of button 106. As illustrated in FIG. 8 b, thebutton 106 may include locking or ratcheting teeth 152 to give tactilefeedback of its location, and to positively retain the button and theassociated leg 141 in an extended or retracted position. Several matingteeth 148 are located underneath groove 146, and a spring member 150 isattached to button 106 to exert pressure against the base of groove 146,to engage mating teeth 148, 152. When a force is applied on the top ofbutton 106, the interlocking sets of teeth are disengaged and button 106can move freely. Upon achieving the desired extension or retraction ofthe leg 141, button 106 is released and is retained place by the engagedteeth 148, 152.

FIG. 9 a illustrates a top view of cradle 116 in an embodiment in whichthe cradle 116 is formed by two legs 141, 142 of retractor 112. Thedistal end of the legs form “U”-shaped side guides. The top 144 of thedistal portion of the “U” is preferably flattened. This providesatraumatic support for the target vessel retained within cradle 116.Additionally, by minimizing the thickness of distal portion 144, contactwith other devices in close proximity with retractor 112 is minimized.

The cradle 116 may have other effective shapes, for example, asillustrated in FIG. 9 b in which a “C” ring element is attached to legsof the cradle 116. The “C” ring may have a small hole 200 in one sidewith an axis approximately parallel to the axis of the retractor 112.This hole 200 is used to hold suture or other ligating materials, andmay also be used as a knot pusher. As shown in FIGS. 10 a and 10 b, inan alternate embodiment of the embodiment of FIG. 9 b, the retractor 112is formed and flattened and a “C”-shaped ring is coupled to theretractor 112 by, for example, gluing or molding the “C” ring to thedistal end of the retractor 112, as shown in FIG. 10 c and 10 d.

Referring back to FIGS. 9 c, 9 d, and 9 e, the side guides of the cradlemay include a loop 129 in a “V” shape, an arced “U” shape, or asemi-circular shape. In one embodiment, as illustrated in FIG. 9 f, theretractor 112 has only one leg 141, and the cradle 116 is formed by theleg 141. A stopper 160 is coupled to the end of the leg 141 to serve asa guide to retain the target vessel, and add a blunt surface to the endof the wire, for example, for pushing and probing tissue. FIG. 9 gillustrates a retractor 112 having a spur 204 formed in one or both legs141, 142 for allowing the retractor 112 to be used for dissection.Sinusoidal, half-sinusoidal, and other geometric configurations may beused equally effectively as the shape of loop 129 in accordance with thepresent invention.

FIG. 11 a illustrates a perspective side view of a cannula 100 and anirrigation effector 1150 for cleaning an endoscope lens 1108 and wettinga surgical site. In the embodiment of FIG. 11 a, the irrigation effectoris retractor 112. As described above, the retractor 112 extends distalto the tip of the cannula 100 responsive to activation of a controlbutton 106. In one embodiment, two supporting members 1100, 141 attachto the dissection cradle 116 and allow it to extend and retract. Asshown in FIG. 11 b, one supporter or leg 1100 is hollow, functioning asa lumen to carry irrigation fluid for cleaning an endoscope lens 1108(shown in FIG. 11 c). An irrigation nozzle 1104 is disposed on thecradle 116 or on the distal portion of the hollow leg 1100 and isconfigured to spray irrigation fluid at the endoscopic lens 1108. Theirrigation fluid is received from a fluid source which conducts thefluid under pressure to the leg 1100. When the retractor 116 is slightlyextended out of the distal end of the cannula 100, the irrigation nozzle1104 is directed toward the lens 1108 of the endoscope 126 at an angleapproximately normal to the endoscope lens 1108, allowing a spray ofirrigation fluid to contact the surface of the lens 1108 and clean thelens 1108 effectively. Additionally, as the spray is directed backtoward the endoscope 126, the surgeon is able to view the source of thespray through the endoscope 126, and is able to adjust the angle ofincidence by adjusting the extension of the retractor 112. Thus, byhaving the endoscopic washing system built into the cannula 100 and intothe sliding retractor 112, a more effective cleaning system is providedthan what is provided by systems which are built into the endoscopeitself.

If the surgical site requires irrigation, the dissection cradle 116 isextended out of the cannula 100, as shown in FIG. 11 a, toward the arearequiring irrigation. Upon reaching the site under endoscopicvisualization, the surgeon can direct a spray of irrigation fluid towardthe site. Again, if the site is not properly irrigated, the surgeon canadjust the positioning of the retractor 112 until the spray hascontacted the surgical site. Thus, the irrigation system of the presentinvention can both wash the endoscope lens 1108 and irrigate a remotesurgical site.

As shown in FIG. 11 c, the hollow leg 1100 is situated within a lumen1112 in the cannula body 100. An extension tube (not shown) is connectedto the proximal end of the lumen 1112 to provide a source of irrigationfluid under pressure, for example, via a Luer lock syringe fitting. Thesyringe is used to selectively inject fluid under pressure into thelumen 1112 upon a determination that the endoscope lens 1108 requirescleansing. The hollow leg 1100 may extend only a fraction of the lengthof the lumen 1112 within the cannula body 100 prior to coupling toirrigation fluid under pressure. However, the hollow leg 1100 should beof sufficient length to extend the cradle 116 out to its proper workingdistance. To minimize leakage of irrigation fluid, the hollow leg 1100has an outer diameter that slip fits within the inner diameter of thecannula body lumen 1112. Alternatively, as shown in FIG. 11 d, thehollow leg 1104 has an outer diameter smaller than the inner diameter ofthe cannula body lumen 1112, but has a proximal end 1120 that flares outto a slip fit within the cannula body lumen 1112. These relativedimensions allow irrigation fluid to be dispensed through the cannulabody lumen 1112, into the hollow leg 1100 and out the irrigation nozzle1104 without significant leakage past the hollow leg 1100.

FIG. 11 d illustrates an embodiment of the single-leg irrigation systemin which a wire 141 is present within the hollow leg 1100 in lumen 113.The presence of wire 141 provides support and rigidity to the retractor112 while retaining the ability of the hollow leg 1100 to be used toconduct irrigation fluid to the irrigation nozzle 1104.

FIG. 12 is a cut-away side view of a multi-tube embodiment of acannula-based irrigation system. In this embodiment, the hollow leg 1200includes a semi-rigid flexible tube or the like, and extendsapproximately one quarter to one third of the length of the cannula body100 within a second irrigation tube 1204 inside of the cannula bodylumen 1112. A fluid input tube 1208 of flexible plastic attaches to theproximal end of the irrigation tube 1204 and extends out of the cannulahandle 104. The proximal end of the fluid input tube 1208 may include avalved Luer lock fitting 1212 for connection to a source of irrigationfluid such as provided by a syringe by selective applications ofpressure. The first tube 1200 is slidable within the irrigation tube1204 to form an adequate sliding fluid seal between the moving parts.

FIG. 13 is a cut-away side view of a separate lumen irrigation system.In this embodiment, the cannula 100 contains a separate irrigation lumenin the cannula body The lumen ends in a spray nozzle 1300 on the distaltip of the cannula 100. The tip of the nozzle 1300 is approximatelyparallel to the lens 1108. Cleansing is accomplished by applyingspraying irrigation fluid across the lens 1108 to wash the lens 1108.The irrigation fluid is supplied to the irrigation lumen by a fluidinput tube 1208 as described above in FIG. 12, and the proximal end ofthe fluid tube 1208 may be attached to a syringe as a source of theirrigation fluid under selective pressurization. The syringe may beremoveably attached to the cannula handle 104 to prevent the syringefrom moving or dangling from the handle 104, and obtruding onmanipulation of the cannula 100 during vessel harvesting.

FIG. 14 a is a perspective front view of a single leg irrigation systemand shows the distal end of the cannula 100 housing the cradle 116 andthe endoscope 126. In this embodiment, the dissection cradle 116 issupported by one leg 141 (shown in FIG. 11 b) within a first lumen 1408within the cannula body 100, and a cannula body lumen 1412 not occupiedby the second leg of the cradle 116, as in embodiments previouslydescribed, is fitted with a nozzle 1400 which sprays the endoscope lens1108. The spray nozzle 1400 is directed at an angle at which theendoscope lens 1108 can be sprayed directly and effectively forcleaning. FIG. 14 b is a perspective side view of the single legirrigation system and shows the distal end of the cannula 100 and thelocation of the spray nozzle 1400.

FIG. 15 is a flowchart illustrating a method for washing an endoscopiclens 1108 and remote surgical site in accordance with the presentinvention. First, skin is incised 1500 at an area near a target vessel.Next, the device is advanced 1504 under endoscopic visualization towardthe surgical site. If the surgeon determines 1506 that the surgical sitehas been reached, then the surgeon determines 1520 whether the surgicalsite requires irrigation. If the surgical site requires irrigation, thesurgeon extends 1524 the retractor 112 toward the surgical site andactivates 1528 the irrigation system to wet the surgical site. Thesurgeon determines 1532 whether the site is sufficiently wet by viewingthe site through the endoscope 126. If the site is sufficiently wet, theprocess ends. If the site requires more irrigation, the surgeonpositions 1536 the retractor 112 under endoscopic visualization todirect the spray more accurately at the surgical site.

If the surgical site has not been reached, the surgeon determines 1508whether the lens 1108 is clean. In response to the lens 1108 becomingobscured with blood, fatty tissue, or the like, the irrigation system isactivated 1512 in situ to wash the lens 1108. In one embodiment asdescribed above, the retractor 112 is extended until the angle of thespray is approximately normal to the surface of the endoscopic lens1108, and therefore effectively washes the lens 1108. Next, the surgeondetermines 1514 whether the lens 1108 has been cleaned satisfactorily.If not, the retractor and thereby the irrigation nozzle 1104 isselectively positioned 1516 via extension or retraction of the retractor112 under endoscopic visualization to direct the spray toward the lens1108 at a more effective angle. The surgeon can continue to repositionthe retractor 112 until the spray nozzle is directed at an effectiveangle toward the lens 1108.

FIG. 16 a shows a cut-away side view of another embodiment of acannula-based irrigation system. In this embodiment, a nozzle tube 1600is extendable from within a lumen 113 in the cannula 100. The proximalend of the nozzle tube 1600 is attached to a distal end of a tensionspring 1604, whose proximal end is stably attached on the side of thelumen 113 or at the proximal end of the cannula 100. The tension spring1604 biases the nozzle tube 1600 in a retracted state. Upon exposure tohydraulic water pressure, as shown in FIG. 16 b, the liquid pushes thenozzle tube 1600 out of the lumen to a point slightly beyond theendoscope lens 1108. The liquid flows inside the nozzle tube 1600 andexits out the spray hole 1608, spraying irrigation fluid back towardsthe endoscope lens 1108.

Thus, the irrigation systems described above provide an effective methodof cleaning an endoscope lens 1108 without requiring the removal of theendoscope from a surgical site. Additionally, the washing systemdescribed above is more effective due to the use of a spray nozzleexternal to the endoscope, which allows the angle of spray to bedirectly projected against the endoscope lens 1108. In an embodiment inwhich the irrigation nozzle 1104 is disposed on the cradle 116 or on thehollow leg 1100, a surgeon can visually adjust the angle of incidence ofthe spray, and can also irrigate a surgical site by adjusting theextension of the retractor 112 out of the cannula 100.

What is claimed is:
 1. A surgical apparatus for generating an irrigatingspray comprising: an elongated cannula having an axis between distal andproximal ends, and a retractor, slidably supported on at least onehollow supporter relative to the cannula for translational movementsubstantially aligned with the axis of the cannula, and including anirrigation nozzle disposed near the distal end of the hollow supporter,the hollow supporter conducting irrigation fluid to the irrigationnozzle.
 2. The apparatus of claim 1 wherein the irrigation nozzle isdisposed in a side of the hollow supporter near the distal end thereof.3. The apparatus of claim 1 wherein the hollow supporter is disposedwithin an irrigation conduit in the cannula and a proximal end of theirrigation conduit includes a fluid inlet.
 4. The apparatus of claim 3wherein the hollow supporter is semi-rigid plastic tubing that isslip-fitted within the irrigation conduit near the distal end of thecannula.
 5. The apparatus of claim 1 wherein the cannula furthercomprises a retractor lumen therein for supporting the hollow supporterin slip-fitting relationship with the retractor lumen.
 6. The apparatusof claim 1 wherein the retractor further comprises a dissection cradle,disposed at the distal end of the retractor, and the irrigation nozzleis disposed in the dissection cradle that includes a conduit therein influid communication between the hollow supporter and the nozzle.
 7. Theapparatus of claim 1 further comprising a tension spring, having adistal end attached to the distal end of the hollow supporter, forallowing the extension of the distal end of the hollow supporter beyondthe distal end of the cannula responsive to an application of pressure,and retaining the hollow supporter in a retracted position otherwise. 8.The apparatus of claim 1 wherein an endoscopic lumen is disposed in thecannula, and the irrigation nozzle is directed toward a distal end ofthe endoscopic lumen.
 9. A surgical apparatus for generating anirrigating spray comprising: an elongated cannula having an axis betweendistal and proximal ends, and a retractor, slidably supported on atleast one hollow supporter relative to the cannula for translationalmovement substantially aligned with the axis of the cannula, comprising:an irrigation nozzle disposed near the distal end of the hollowsupporter, the hollow supporter conducting irrigation fluid to theirrigation nozzle; and a dissection cradle, disposed on the distal endof the retractor, for retracting tissue upon extension from the cannula.10. The apparatus of claim 9 wherein the irrigation nozzle is disposedon the dissection cradle.
 11. The apparatus of claim 9 wherein anendoscopic lumen is disposed in the cannula, and the irrigation nozzleis directed toward a distal end of the endoscopic lumen.
 12. A methodfor cleansing an endoscope lens at a distal end of an elongated cannulathat slidably supports a retractor for selectable extension from thedistal end of the cannula and that includes an irrigation system,comprising the steps of: incising skin at an area near a target vessel;advancing the cannula through the incision towards a target site underendoscopic visualization through the endoscope lens at the distal end ofthe cannula; selectively extending the retractor to position a spraynozzle thereon to wash the lens of the endoscope and selectivelyactivating the irrigation system for washing the endoscope lens.
 13. Themethod of claim 12 further comprising the step of: selectively extendingthe retractor to retract tissue encountered during advancement of thecannula.
 14. A method of irrigating a remote surgical site using anelongated cannula that slidably supports a retractor for selectableextension from the distal end of the cannula and that includes anirrigation system, comprising the steps of: incising skin at an areanear a target vessel; advancing a cannula through the incision towardsthe surgical site under endoscopic visualization; responsive to thesurgical site requiring irrigation, selectively extending the retractortoward the surgical site; and activating the irrigation system forwetting the surgical site.
 15. A method of irrigating a remote surgicalsite using an elongated cannula that slidably supports a retractor forselectable extension from the distal end of the cannula and thatincludes an irrigation system, comprising the steps of: incising skin atan area near a target vessel; advancing a cannula through the incisiontowards the surgical site under endoscopic visualization; selectivelyextending the retractor to retract tissue; responsive to the surgicalsite requiring irrigation, selectively extending the retractor towardthe surgical site; activating the irrigation system for wetting thesurgical site.